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The supplied quick disconnect fittings allow the FirstLook
®
Fuel
Injection Sensor to be used with virtually any commercially
available Fuel Pressure Test Kit and adaptors.
Using the FirstLook
®
sensor is in addition to the necessary electrical tests
that need to be performed before condemning any injector. This sensor
checks flow of a given injector. With that said low flow can come from
a voltage drop in the injector circuit, or a faulty driver in the PCM. The use
of a low amps current probe and or a voltage drop test to confirm circuit
integrity is crucial to get the full picture of what is going on with any
injector. Remember low flow can be caused by an electrical problem as
well as a flow problem within the injector. It is up to you to determine
where the low flow problem area is. What this sensor does is locate which
injector is having the problem. To get the whole picture one needs to
know both the electrical and the physical information to make this
decision. This sensor will finally give you the piece of the puzzle you have
never had before.
IMPORTANT: The sample line and sensing cavity must be
purged of air for the signal to be a true reaction to pressure
changes in the fuel rail.
The physical difference between injectors.
It is important to discuss some of what you might find using
this sensor to head off any false conclusions. First, practice on a
known good vehicle. Depending on how you trigger your scope (#1
injector, #1 ignition or cam sensor) you will notice that #l injector can
start from before the trigger point or after the trigger point. The best
way to know for sure is to have the correct firing order for the engine.
Next with the key off, disconnect one of the injectors. Follow the firing
order and see if the pattern reflects the cylinder you think it is. With this
confirmed you can be very confident you have located the problem
injector. Now it is up to you to diagnose if it is the injector itself or an
electrical problem with the harness or PCM.
You will find that with practice you will develop your own routine procedure
depending on whether you favor using a current ramping probe, ignition
or even voltage signature to sync the firing order of the injectors.
Connect FirstLook
®
Injection Sensor using the quick disconnect fitting
supplied in the kit and when necessary the appropriate fitting from your
fuel pressure test kit to connect to the fuel injection rail of vehicle being
tested.
